I recently flew EWR-LHR-EWR return in the same GE90 powered 777 model as G-VIIO, and since the implementation of the new carry-on regulations. My roll-along went in the overhead, and my smaller bag for my laptop, which also included some medications, toiletries, wallet, passport, etc, was given a yellow label saying handbag/laptop bag, and this bag must be placed under the seat in front of you. I have no disagreement at all with all the arguments about leaving cabin baggage with wheels, indeed everything placed in the overheads, right there in the overheads in the event of an evacuation. However, with a light bag on the floor, I'd say it was far safer to pick it up and take it with me on leaving the plane in an emergency, rather than it remaining on the floor.